Research On Microseismic Location Algorithm Based On Geophone Weight Factor Constraint

Hydraulic fracturing microseismic monitoring research was a discipline based on acoustic emission phenomena which caused by rock breaks or stratigraphic displacement in subsurface rocks.With the continuous development and evolution of positioning algorithms,the field of microseismic monitoring has been rapidly developed and matured based on this theory.At present,this method has been widely used in the development of low-permeability oil and gas reservoirs.It provides an intuitive and reliable foundation for the analysis of crack propagation methods and the evaluation of hydraulic fracturing operations.Nowadays,the studies on hydraulic fracturing micro-seismic positioning methods were often focused on the correction of underground velocity models,micro-seismic positioning methods,and source identification.There are still very few studies on the analysis of geophone arrangement and the influence of weight factors on microseismic positioning.Therefore,the research based on the classical grid-based search amplitude superposition microseismic localization algorithm in this situation.Firstly,the influence of the perspective of the geophone on the location of the microseismic is analyzed.Secondly,the microseismic location algorithm based on the weighting factor constraint of geophone is proposed by analyzing several influence factors that affect the geophone data under the condition of the geophone layout of the fractured zone.Finally,the validity and reliability of the scheme are verified by laboratory synthetic data test and field data processing.The specific research contents of this paper mainly include: Under the ground monitoring conditions,using the classical fracstar array arrangement mode,the influence of the different angles of the detectors placed on the positioning accuracy is systematically analyzed,which provides the basis for the subsequent detector weight correction algorithm.Due to the special construction of microseismic monitoring,noise pollution has caused by some arrays or adjacent multichannel detectors during the monitoring process.If these arrays are simply removed,the angle of coverage of the detectors will be incompletely covered.Without removing these arrays,large noise errors will be introduced.In order to reduce the influence of the above problems on the reliability of microseismic positioning,this paper analyzes the amplitude attenuation,epicentral distance,signal-to-noise ratio and other parameters of the waveform picked up by the detector and proposes a dual signal-to-noise ratio and epicentral distance based on the waveform of each detector.Factor weighted microseismic positioning has correct algorithm.The synthetic data shows that the proposed algorithm proposed in this paper can effectively reduce the impact of the above problems on the source location.At the same time,in order to facilitate the use of weighted localization algorithm,this paper integrates Qt,MySQL,MATLAB and Visual Studio 2010 platforms,and uses C++ language to compile three modules: microseismic data transmission,waveform display,and geophone weighted localization algorithm.The micro-seismic data transmission module can acquire the micro-seismic data that needs to be processed in real time,and then passes it to the weighted positioning algorithm module to perform micro-seismic event location;the waveform display module can display the waveform of the micro-seismic data collected in real time or selectively.It can be used as a proof of the results of the weighted positioning algorithm.Finally,the above-mentioned weighting algorithm is used to give the processed positioning results to be presented by means of a micro-seismic event display program developed by Jilin University's Institute of Electrical and Electronics.The original microseismic positioning method and the microseismic weighted localization algorithm proposed in this paper was used to process the actual data of a field hydraulic fracturing microseismic monitoring,and the positioning results were analyzed,and the final fracturing results were given to verify the proposed detection based on this paper.The validity of the microseismic algorithm with the constraint of geophone weight factor is verified.